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[net,2/7] mptcp: pm: deny endp with signal + subflow + port

Message ID 20240731-upstream-net-20240731-mptcp-endp-subflow-signal-v1-2-c8a9b036493b@kernel.org
State Accepted
Commit 8af1f11865f259c882cce71d32f85ee9004e2660
Headers show
Series mptcp: fix endpoints with 'signal' and 'subflow' flags | expand

Commit Message

Matthieu Baerts (NGI0) July 31, 2024, 11:05 a.m. UTC
As mentioned in the 'Fixes' commit, the port flag is only supported by
the 'signal' flag, and not by the 'subflow' one. Then if both the
'signal' and 'subflow' flags are set, the problem is the same: the
feature cannot work with the 'subflow' flag.

Technically, if both the 'signal' and 'subflow' flags are set, it will
be possible to create the listening socket, but not to establish a
subflow using this source port. So better to explicitly deny it, not to
create some confusions because the expected behaviour is not possible.

Fixes: 09f12c3ab7a5 ("mptcp: allow to use port and non-signal in set_flags")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_netlink.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 37954a0b087d..c921d07e5940 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1328,8 +1328,8 @@  int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info)
 	if (ret < 0)
 		return ret;
 
-	if (addr.addr.port && !(addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
-		GENL_SET_ERR_MSG(info, "flags must have signal when using port");
+	if (addr.addr.port && !address_use_port(&addr)) {
+		GENL_SET_ERR_MSG(info, "flags must have signal and not subflow when using port");
 		return -EINVAL;
 	}